You can export your tree into a Gedcom file. You can do this by going to the My Family Tree link at the top of the website and then select to view all trees.
You will then see all of the trees that you have created.
There are icons to the right of each named tree. If you hover over them with your mouse, you will see the one which is named 'export tree', please just click on this icon to begin the export process.
Once complete, you will see that your tree has been saved as a file to your computer.
If you do not already have Gedcom software loaded to your PC, you can get a free Gedcom software download from various websites on the internet.